一株分离自红树林沙雷氏菌的鉴定及杀虫活性测定

【目的】为开发用于害虫生物防治的细菌杀虫剂,对分离自红树林的一株沙雷氏菌进行鉴定并初步测试其杀虫活性。【方法】采用形态特征比较、细菌理化特性测定和基于16S rDNA序列构建系统发育树对从湛江红树林根际分离的菌株ZJ9进行综合鉴定,采用喂毒法和注射法进行杀虫活性测定。【结果】该菌为黏质沙雷氏菌Serratia marcescens,对草地贪夜蛾3龄幼虫7d校正死亡率为80.21%,且与苏云金芽孢杆菌和隐地杆菌无显著差异,菌体及菌液对大蜡螟老熟幼虫血腔注射24 h死亡率均达100%。【结论】菌株ZJ9为黏质沙雷氏菌,对草地贪夜蛾具有很好杀虫活性,可用作害虫的生物防治资源。

Identification and Insecticidal Activity of a New Strain of Serratia Isolated from Mangrove Forest

【Objective】To exploit new bacterial insecticide for the biological control of pests;a strain of Serratia isolated and identified from mangrove forest was used in the preliminarily insecticidal activity tested.【Method】ZJ9 strain isolated from rhizosphere of mangrove in Zhanjiang was comprehensively identified by morphological feature comparison,physicochemical properties of bacteria and 16S rDNA sequence by phylogenetic tree analysis.The insecticidal activity was determined by the feeding and injection method.【Result】The identified bacteria was Serratia marcescens,and it has a corrected mortality of oral toxicity of 80.2%in the 3rd larva of Spodoptera frugiperda.It was not significantly different from that of Bacillus thuringiensis and Empedobacter brevis.The mortalities of injection toxicity to mature larvae of Galleria mellonella were both 100%either in the cell or extracellular fluid.【Conclusion】The Serratia marcescens ZJ9 strain has good insecticidal activity on Spodoptera frugiperda and it can be used as a biological control agent.